How Much Does It Cost to Build a Fourplex in 2025?

Average Cost to Build a Fourplex

Fourplex Building Cost Factors

As the name implies, a fourplex is one building separated into four separate living units. These units will range anywhere from 500 square feet to more than 1,200 square feet.

Cost per Unit

The average cost to build a fourplex per unit is around $263,500. However, you may pay anywhere from $155,000 to $372,000 per unit, depending on size, location, and what upgrades you choose to include in your units.

Fourplex Type

Fourplexes are often two-story buildings with two units on each side and one unit on each floor. You may find single-story fourplexes with the units side-by-side from each other.

Two-Story Fourplexes

Two-story fourplexes will cost anywhere from $135 to $350 per square foot to build. You typically enter these units from the front or back of the building through the ground floor or by taking the stairs to the second level. However, there are fourplexes in which each unit has its own private entrance, and the stairs for each upper unit are located on the side of the building.

Single-Story Fourplexes

Single-story, side-by-side fourplexes will cost around $100 to $155 per square foot to build. While single-story fourplexes require fewer material costs, it’s often harder to accomplish this type of building because you’ll need a much larger lot than a two-story option, increasing the cost of land.

Components and Rooms

Whether it’s a single-family home, townhome, duplex, or fourplex, you’re going to use the same materials to build the structure. While the costs of foundations and drywall prices may not increase too much compared to other home options, keep in mind you need to finish four separate kitchens and at least one bathroom in each unit.

Common materials and pricing for building a single unit in a fourplex include:

Keep in mind that this estimate doesn’t include additional details, such as doors, lighting fixtures, and common area materials. You’re going to need to purchase and install features such as mailboxes, a flight of stairs to access the upper units, and fire exits. In some states, such as California, you may also have to install systems like fire sprinklers and solar panels.

Other Fourplex Building Cost Factors

Beyond the basic construction prices of building a fourplex, you’ll have to consider a few other variables that can drastically change your final costs. These include labor, permits, various other expenses, and any amenities you choose to invest in.

Labor

Any housing project requires a wide range of professional teams to accomplish the building task. You’ll also likely need to hire an architect and a structural engineer to ensure your fourplex is up to safety standards.

Here’s a general list of the professionals you’re likely going to need to hire on a fourplex project:

Permits

The cost of permits will vary based on location and local municipal codes. For example, one area may charge a flat fee of $4,220 for zoning and construction permits, while other areas may charge a percentage of the total cost of the project. This percentage may range anywhere from 0.01% to 1% of the project’s total cost.

Other Expenses

When taking on a significant building project, you can expect to run into unexpected costs.

Depending on location and lot size, you may need to build a designated parking space for at least one vehicle for each unit. If you’re looking for a simple lot with no overhead coverage, you should expect to pay around $2.50 to $7 per square foot to pave a parking lot.

Other unexpected expenses may include fire escapes, roof access, and accessibility access to each unit (this may mean installing elevators).

Amenities

Beyond the home itself, there are individual choices you may want to make as a landlord to make the units more appealing, including shared amenities or a covered parking area.

Covered Parking Lot

Building a carport over the parking lot may help you attract tenants to your rental units. A covered parking lot offers protection from the weather and the sun, allowing for cool cars and potentially less damage from falling debris and hail. If you plan to provide every unit with a single carport, expect to pay $6,275 per unit.

If you’re looking to build a carport that covers the entire parking lot, you should contact a local carport builder to get exact quotes for your lot.

Preinstalled Smart Technology

Many landlords are looking to stay on top of tech trends by installing smart home technology in their units. These smart amenities can include smart locks and smart thermostats, which allow tenants to control their front door and thermostat remotely. Adding smart home tech costs around $1,600 per unit on average.

Interior Furnishings

It’s not uncommon to see rental properties fully furnished as a way to increase the value of the home and decrease the amount of furniture a potential tenant needs to buy. The average cost to furnish an apartment is around $4,650 per unit.

Security System

You may want to opt for a security system for the property itself, as well as for the individual units. The cost of installing a home security system is around $900 on average, and you’ll need one for each unit. Though the installation cost may not be as pricey for individual units as the property itself, the cameras on the outside will act as cameras for every unit.

Other Amenities

Adding top-notch amenities like a shared gym or swimming pool is a great way to attract tenants and increase rent prices. To help your property stand out, you could pave past the parking lot and create a small basketball court or give tenants the ability to store items on-site.

The cost of installing a free-throw basketball court sits between $4,000 and $20,000 on average. Building a single-story storage facility will cost around $50 per square foot.

Budgeting for Building a Fourplex

A fourplex is an extremely expensive project to take on, but it might be the right choice if you’re looking to build a dream home for you and your family or if you plan to make it an investment property. Here are a few ways to reduce the costs of building a fourplex:

• Take plenty of time in the planning phase to ensure you’ve considered every expense from the beginning.

• Make the investment in experienced, skilled local home building contractors who will do the job right the first time.

• Use cost-effective materials wherever possible.

• Invest in an experienced architect to identify cost-saving design choices.

• Take your time when creating a construction timeline and budget to ensure you can predict expenses.

• Take out a construction loan to finance your project.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.